A controlled spinal cord contusion for the rhesus macaque monkey

Area of Science:

• Neuroscience
• Regenerative Medicine
• Animal Models

Background:

• Rodent models of spinal cord injury (SCI) have limitations due to anatomical and functional differences with humans.
• There is a critical need for large animal models, like non-human primates, to bridge the gap between laboratory research and clinical applications for SCI.

Purpose of the Study:

• To establish a controlled, clinically-relevant contusive spinal cord injury model in non-human primates.
• To characterize the severity-dependent functional and histological outcomes of this new SCI model.

Main Methods:

• Adult male rhesus macaques underwent mild to moderate contusive SCI (1.0 or 1.5mm tissue displacement) or sham laminectomy.
• Functional assessments included motor-evoked potentials (MEP), somatosensory-evoked potentials (SSEP), and the monkey hindlimb score (MHS).
• MR imaging (including DTI tractography) and histological analysis of lesion sites were performed at various time points up to 6 months post-injury.

Main Results:

• The monkey hindlimb score demonstrated severity-dependent neurological deficits.
• MEP response rates were depressed or abolished, and SSEP showed slight decreases post-injury.
• MRI revealed lesion site changes, DTI showed interrupted fiber tracts, and histology confirmed severity-dependent spinal cord atrophy, axonal degeneration, and myelin loss.

Conclusions:

• A reproducible, severity-dependent contusive spinal cord injury model was established in non-human primates.
• This model exhibits functional and histological deficits relevant to human SCI, potentially facilitating the translation of therapeutic strategies.
• The absence of strong astrocytic gliosis in the lesion penumbra of this model warrants further investigation.